The present invention relates to an infrared gas analyzer. More particularly, the present invention relates to an infrared gas analyzer which includes a measuring chamber, container, a cuvette and a chamber, cuvette or container for a reference gas. Moreover, down stream from these two containers a radiation receiving device is provided using the principle of obtaining and ascertaining a pressure differential on account of different absorption in the receiving chambers. Infrared gas analyzers to which the invention pertains uses specific radiation absorption sections (bands) multi-atom, non-elementary gasses having particularly absorption bands in the infrared range, and the absorption cahacteristics and capabilities of such a gas are used for purposes of obtaining measurement, particularly quantitative measurements of gas components in a host gas. Upon using two parallel beams separately intercepted by receiver chambers pressure differentials are an indication of differences in absorption by the content of the measuring and reference chambers. The measuring gas is usually run through an analyzing and measuring chamber on a continuous basis. That chamber is placed in one radiation beam path. The reference chamber is disposed as stated to be passed through by the second beam and contains a gas, for example, that does not absorb infrared radiation. Depending upon the concentration of the measuring component in the host gas that flows through the analyzing and measuring chamber, and with reference to a (normally) constant value as provided through the reference chamber, one will obtain a particular differential in radiation on the exit side of these chambers, and that differential is then measured through the receiving chambers mentioned above. Moreover, the beams are periodically interrupted (modulated) so that the relevant measuring and reference quantities appear as an amplitude modulation. The difference in radiation causes different heating and therefore different pressures in the two receiving chambers which are suitably placed to intecept the two beams after they traverse the measuring and reference chambers. The two receiving chambers are interconnected so that a pressure differential difference can be measured. Usually, a membrane capacitor is used here with a flexible membrane that deflects depending on the pressure differential on both of its sides, and this deflection is converted into an electrical signal to be suitably ascertained.
Infrared gas analyzers of the type mentioned above are, for example, described and disclosed in a data sheet distributed by applicant's assignee under the number 20-1.12, and published May, 1983. Further, for the state of the art generally, reference is made to the following patents by applicant's assignee: U.S Pat. Nos. 4,373,137, 4,288,693, 4,281,248, 4,190,732, 4,156,812, 3,937,962, 3,925,667, and 4,496,840. These various gas analyzers use different techniques, but in many and all instances the principle of chopped reference and measuring beams, and of separately measuring these two beams under utilization of absorption techinques then called upon in a differential mode, is widely used throughout.